The greatest game on Earth begins the way it ended earlier this year, with a matchup between the Denver Broncos and the Carolina Panthers. Back in February, it was a swan song for Peyton Manning, an appreciation of Wade Phillips and living proof that defense wins championships no matter how loaded your offense might be.

A lot has changed since then. Manning is gone. So is his backup, Brock Osweiler. So is boisterous cornerback Josh Norman. The emotions remain high.

Here is what we're watching tonight:

1. Trevor Siemian and the real Broncos offense: Last year's offense in Denver was a tug of war between Peyton Manning's frantic shotgun spread and Gary Kubiak's rollout run-first scheme. They met in the middle with a Pistol-type version of the offense, but between Manning's alterations and a few quarterback changes due to injury, we were never able to see the first-year head coach's true vision. Enter Siemian, a surprise draft pick who spent his first year in Denver learning the nuances and this offseason outlasting Mark Sanchez and first-round pick Paxton Lynch in the preseason to win the job.

Siemian can take care of the ball and has a higher upside than the mistake-prone Sanchez. This is the best offense he'll likely ever have the chance to pilot, and he knows Kubiak won't be hesitant to make a change with a high-profile rookie on the bench. As they say, pressure creates diamonds, and Siemian's arrival onto the grand stage will be against the best front seven in football.

2. The poise of Cam Newton: The Super Bowl gave us a troubling glimpse of what Newton is like when he's rattled: long, erratic passes, forced throws and a general dimming of his inner spark. Watching Newton for a majority of the season last year was a privilege. When everything is rolling for Newton, he plays some of the most incredible, artful football in the league and the Panthers' offense looks next to unstoppable. Add in some pressure and the parameters change just as they do for any quarterback staring down a relentless pass rush. So which quarterback will we see tonight? Newton has the chance to pick up where the NFC Championship Game left off, or he has the burden of wearing the Super Bowl loss for another week.

3. Denver's offensive line against Kony Ealy, Kawann Short, Star Lotulelei and Charles Johnson: If Denver's "replacement level quarterback" experiment is going to work, they are going to need a banner performance from their offensive line when everyone in the league already knows what's coming. Tackle Russell Okung was added to the mix, but Ryan Clady is with the Jets and Evan Mathis now plays for the Cardinals. It will be a difficult band of veterans to replicate, especially against a young Panthers defensive line that is getting better by the day.

4. The reintroduction of Kelvin Benjamin: The Panthers' dynamic receiver missed all of last season with a torn ACL. His snap count over the first few weeks of this season will be the subject of much debate if the team continues to ease him back into action. Panthers fans this season remind us a bit of Giants fans last year, envisioning the combination of Victor Cruz and Odell Beckham as if injury, time and circumstance have no effect. The hesitations can be had for Benjamin, Devin Funchess and Greg Olsen. On paper, it is a trio we would freely stack up against any in football, but Carolina is starting with a clean slate in 2016.

5. The (latest) finger-wagging by Dave Gettleman: The Panthers' general manager has scolded us in the past for not believing him. Gettleman took a lot of heat for allowing Norman to walk away from the Panthers and into a lucrative pact with Washington this summer, placing faith in a system that produced one of the league's toughest defenses a year ago. Now, he's trying to replicate success with rookie second-round pick James Bradberry, rookie third-round pick Daryl Worley and Bene' Benwikere. Some football people will argue that this is cost-cutting genius, and that a front seven with this much talent leads to success -- not the other way around. Still, a very good general manager in Washington snapped up Norman without a moment's hesitation. Who is right? We could find out soon.